This invention is concerned with the specific problem of the early detection of mastitis in cows. The most common early indication of mastitis in a cow is abnormal milk containing clots.
The commonly recommended method for the detection of clots in milk was the foremilk cup, which enabled the first milk from each cow to be examined by the herdsman before normal milking. In practice, many herdsmen do not use the foremilk cup, both because of the time the routine takes and because, in the event of an infected cow, the foremilk cup can act as a reservoir of mastitis pathogens, so spreading the infection from cow to cow.
In 1969, an in-line milk clot detector was developed by the National Institute for Research in Dairying at Reading, England. This detector consisted of a stainless steel mesh filter element moulded into a 15 mm bore transparent polycarbonate tube at an angle of 45.degree. thereto. This filter certainly detected milk clots but, being of small surface area, it quickly blocked if milk clots or debris were present. Blocking adversely affected the vacuum conditions at the teat end of the line so that the milking claw might fall off the cow being milked.
The above noted in-line milk detector was preceeded by a Johnson and Johnson clamshell type filter. However, its construction was such that it did not permit good observation of the milk clots and it was not sufficiently hygienic. The above noted in-line milk clot detector was an attempt to improve upon this earlier device.
Both of the two methods above-described having proved unsatisfactory in practice, there existed therefore a great commercial need for an in-line mastitis detector for use in milking parlours which would not block during the milking and clot-detection operation and which could be easily and thoroughly cleaned both in the normal in-place cleaning of the milking plant by the established methods and in respect of any milk clots trapped.